"We already know that while many people experience sexual activity," says head researcher Justin Garcia, "the circumstances, meaning and behavior is different for each person. Some will experience sex with committed romantic partners, others in uncommitted one-night stands….What we didn't know was how we are motivated to engage in one form and not another, particularly when it comes to promiscuity and infidelity."

Garcia and his team took DNA samples of 181 adults and recorded a detailed history of their sexual pasts. They found that genetic variations influenced sexual behavior.

"What we found was that individuals with a certain variant of the DRD4 gene were more likely to have a history of uncommitted sex, including one-night stands and acts of infidelity," says Garcia. "The motivation seems to stem from a system of pleasure and reward, which is where the release of dopamine comes in. In cases of uncommitted sex, the risks are high, the rewards substantial and the motivation variable—all elements that ensure a dopamine rush.'"

Is this gene a sentence? Garcia explains: "… not everyone with this genotype will have one-night stands or commit infidelity. Indeed, many people without this genotype still have one-night stands and commit infidelity. The study merely suggests that a much higher proportion of those with this genetic type are likely to engage in these behaviors."

According to the study, an individual's genetically induced desire for sex may operate independently from serious committed feelings and romantic attachments. In other words, a person could have the need for the dopamine rush they get from sex with randoms—and still be totally in love with his or her partner.

FINAL NOTE: DNA is not an excuse for you to stay with someone who cheats. Do not provide your guy with an excuse. Find another guy who behaves differently.

Were you surprised by these findings? We already know about dopamine rushes and addictive personalities, but wasn't it interesting that the gene could cause a person to cheat and still be totally committed (mentally) to his/her partner?